Suppression of Nickel-germanide (NiGe) Agglomeration and NiPenetration by Hydrogen (H) Ion Shower Doping in NiGe on a ThinEpitaxial Ge-on-Si Substrate

Hydrogen (H) ion shower doping was proposed to improve the thermal stability of nickel germanide (NiGe), and its effects were analyzed in depth. As the post-germanidation annealing temperature was increased, the sheet resistance (Rsh) of the undoped sample increased sharply due to NiGe agglomeration while that of the H-doped samples showed a little increase at a temperature above 550 ◦C due to the suppression of NiGe agglomeration and Ni penetration. Hydrogen atoms in NiGe were found to significantly suppress local penetration of Ni atoms out of NiGe and hence contribute to the improvement the thermal stability of NiGe.